The death toll from the Indian Ocean disaster rose dramatically today to 123,000 after Indonesia said almost 80,000 had died in that country alone.

The governments of India, Sri Lanka and Thailand also reported thousands more deaths. In India and Sri Lanka the ordeal of survivors was added to by panic generated by warnings if possible new tsunamis.

As aid agencies struggled to cope with the scale of the disaster, the World Health Organisation warned that the next few days would be critical in controlling any potential outbreak of waterborne diseases, and the money raised by the British public rose to £20m, outstripping the government's contribution of £15m.

Indonesia

Raising its number of victims by more than 30,000, the Indonesian government estimated the country's death toll at 79,940, with officials warning that the body count is still far from complete. Unicef said that close to a million Indonesian children were in need.

Indonesia's Aceh province on the island of Sumatra - the landmass closest to the epicentre of Sunday's seismic activity - bore the brunt of both the 9.0 magnitude earthquake and the subsequent tsunamis.

Aid workers arriving in region have encountered devastation - entire towns and villages razed, and countless people - some of them with cuts and broken bones - searching desperately for clean water and food on streets covered in debris and dead bodies.

Emergency workers and soldiers have come across countless bloated bodies, many of them young children, strewn on the streets and floating in the rivers of Banda Aceh, the provincial capital.

Some survivors have not eaten since Sunday and risk infections and diseases such as elephantiasis, cholera, typhoid, hepatitis, bronchitis, pneumonia, malaria, meningitis and haemorrhagic fever.

Fights have reportedly have broken out in the streets of Banda Aceh over packets of noodles dropped from military vehicles.

Unicef, the international children's agency, estimated that 60% of Banda Aceh has been destroyed, along with severe damage across the north-west coast.

Government institutions have stopped functioning and basic supplies have almost run out, forcing even ambulances to ration fuel. Military helicopter pilots struggled to drop food into isolated villages surrounded by cliffs along the coast of Sumatra, as shortages and the fear of disease spread. [More on Indonesia]

India and Sri Lanka

As the official death toll rose, panic added to the misery of survivors with warnings reported of fresh tsunamis in India and Sri Lanka.

In Sri Lanka, people climbed onto the roofs of their houses while others fled from the coastline after authorities used fire engines equipped with loudspeakers to urge residents to move to higher ground. The country's military urged people to be alert, but not to panic, while an earthquake expert said the aftershocks were probably not strong enough to produce tsunamis.

But with neighbouring India ordering an evacuation of coastal areas, instructions that were heard on radios in Sri Lanka, some people did panic. Cars, vans and motorbikes jammed roads leading away from coastlines. Some people hauled their most valuable possessions stuffed into plastic bags.

"Some people whose houses weren't so badly affected by Sunday's tsunami are also now running toward welfare centres," said Suresh Devaraj, of the coastal town of Trincomalee.

India later denied having issued a fresh warning but said it had urged people to take precautions after information that several aftershocks in the region had pushed up the water level. An estimated 5.7 magnitude underwater earthquake was recorded at 5.18am local time (2118 GMT yesterday) off the coast of Sumatra. Other tremors were felt in Thailand and Burma.

Amid the panic, government officials in Colombo said the country's death toll had risen above 24,000. The Indian government said that 13,268 people were dead or feared dead across the country. In a statement, it said 7,330 were confirmed dead and another 5,900 were missing and presumed dead. All the presumed dead are in the remote Andaman and Nicobar islands, where rescuers have yet to reach isolated areas. [More on India and Sri Lanka]

Thailand

Thailand's official death toll stands at 2,404 - including 713 foreigners - but following a visit to the southern province of Phang Nga, the country's interior minister, Bhokin Balakula, said today that more than 3,500 bodies had been found in that region alone.

It was unclear how many of the 3,500 had been included in the official total, but earlier in the day the prime minister, Thaksin Shinawatra, warned the death toll could rise to 7,000.

"There are many people listed as missing and we think that 80 percent of them are feared dead. Twenty percent may have lost contact," he told reporters.

As Mr Thaksin spoke, rescue and forensic teams from Australia, Japan, Germany, Israel and other countries fanned out across areas of southern Thailand, racing against time to find survivors and identify rapidly decomposing bodies.

Nationals of more than 40 countries were on holiday in six provinces of southern Thailand when disaster struck. They include some 1,500 Swedes, 200 Finns, 200 Danes and hundreds of Norwegians, according to reports from Scandinavian capitals.

"We have to have hope that we'll find somebody," said Ulf Langemeier, the leader of 15 German veterans of earthquake disasters who were using sniffer dogs to comb a wrecked resort with under huge floodlights early today.

Mr Langemeier said there was always a chance of finding survivors trapped under rubble when earthquakes strike on land, but "when waves enter a building you have no chance".

As aid agencies struggled to cope with the scale of the disaster, the World Health Organisation warned that the next few days would be critical in controlling any potential outbreak of waterborne diseases.

The incidence of diarrhoea is increasing, but is no more than expected at this stage of a natural disaster, said the WHO's head of crisis operations, David Nabarro.

"We remain really concerned about the situation," he said, adding that it is becoming clearer whether medical supplies are matching the needs of the affected areas.

With at least 5 million people in need, the relief effort is already one of the biggest humanitarian exercises in history. Sixty countries having pledged more than $220m (£114.5m) in cash and hundreds of millions more in emergency supplies.

Hundreds of tonnes of medical supplies have been flown to the wider region, but the UN admits only a fraction of the aid has got to where it is needed.

"We are doing very little at the moment," said Jan Egeland, the UN's emergency relief coordinator. "It will take maybe 48 to 72 hours more to be able to respond to the tens of thousands of people who would like to have assistance today - or yesterday, rather.

"I believe the frustration will be growing in the days and the weeks ahead," he added.

Singapore has proposed that countries affected by the tsunami should meet within days to develop a strategy to cope with the devastation, while the Italian prime minister, Silvio Berlusconi, has suggested the idea of a special meeting of the G8 group of the world's eight leading industrialised countries. [More on the west's response]